Abstract

K. Balaji, G. V. Raghunadha Reddy, T. Madhusudana Reddy and S. Jayarama Reddy*

A simple, sensitive and accurate voltammetric studies on prednisolone (PE), dexamethasone (DE) and hydrocortisone (HC) were carried out by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) at bare carbon paste electrode (CPE) and -cyclodextrin modified carbon paste electrode (CDMCPE) in Britton-Robinson (BR) buffer solution. PE, DE and HC show marked enhancement of peak currents at CDMCPE when compared to CPE due to the inclusion complex between keto- group from the drug and -cyclodextrin (modifier) . All these compounds exhibit a well-defined single peak in the studied pH range which is attributed to the reduction of keto-group. BR buffer of pH 3.0 was found to be reliable supporting electrolyte for the analytical estimation of these compounds. CV studies indicate that the process was irreversible and adsorption controlled. The reduction peak currents at CDMCPE for PE, DE and HC changes linearly over the concentration range from 5.6 × 10-7 M to 2 × 10-5 M (PE), 4.1 × 10-7 M to 2 × 10-5 M (DE) and 4.2 × 10-7 M to 2.5 × 10-5 M (HC) with a correlation co-efficient of 0.9991, 0.9986 and 0.9995 for the respective compounds. DPV technique is used for the determination of PE, DE and HC in pharmaceuticals and biological fluid samples. For quantification, standard addition method was carried out in both pharmaceutical formulations and biological fluid samples.